Process for producing styrenic polymer

ABSTRACT

There is disclosed a process for producing a styrenic polymer, especially, syndiotactic polystyrene, which comprises polymerizing a styrenic monomer by the use of (a) a transition metal compound, (b) a coordination complex compound comprising an anion in which a plurality of radicals are bonded to a metal and a cation or methylaluminoxane, (c) an alkylating agent (alkyl group-containing aluminum, magnesium or zinc compound) and (d) a reaction product between a straight-chain alkylaluminum having at least two carbon atoms and water (alkylaluminoxane). The above process is capable of simplifying the production process and producing high-performance styrenic polymer having a high degree of syndiotactic configuration in high catalytic activity without deteriorating the catalyst activity, increasing the amounts of residual metals in the objective polymer or leaving the decomposition products of the alkylaluminum therein, thereby curtailing the production cost of the objective polymer.

This application is a continuation-in-part of application Ser. No.08/413,224, filed Mar. 30, 1995, now U.S. Pat. No. 5,596,055.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing a styrenicpolymer. More particularly, it pertains to a process for producing astyrenic polymer having a high degree of syndiotactic configurationefficiently and inexpensively.

2. Description of the Related Arts

In recent years, a process for producing a styrenic polymer having asyndiotactic configuration (hereinafter sometimes referred to as “SPS”)by polymerizing a styrenic monomer by means of a catalyst comprising atransition metal compound as a primary ingredient, especially a titaniumcompound and methylaluminoxane (refer to Japanese Patent ApplicationLaid-Open No. 187708/1987) has been proposed.

There has also been proposed a process for efficiently producing such astyrenic polymer (SPS) by the use of a catalyst comprising acoordination complex compound composed of an anion in which a pluralityof radicals are bonded to a metal and a cation, while dispensing with analuminoxane which is expensive and is to be used in a large amount(refer to Japanese Patent Application Laid-Open Nos. 415573/1990,415574/1990, etc.)

In the case of polymerizing a styrenic monomer by the use of theabove-mentioned catalyst, there has heretofore been employed analkylaluminum as a chain transfer agent for the purpose of modifying themolecular weight of the objective polymer. However, this method involvesthe problems that the catalytic activity deteriorates resulting in anincrease in the amounts of residual metals contained in the styrenicpolymer thus produced, allowing the decomposed product of analkylaluminum to remain in the objective polymer. Even in the case ofraising the polymerization temperature, the deterioration of thecatalytic activity increases the amount of residual metals in theobjective polymer. The aforesaid situation calls for the development ofa process capable of producing a styrenic polymer of high performance ata low cost, while enabling a decrease in the molecular weight of theresultant polymer and simplifying the process itself withoutdeteriorating the catalytic activity.

As a result of intensive research and investigation made by the presentinventors under such circumstances, it has been found that in the caseof polymerizing a styrenic monomer by the use of a transition metalcompound, a coordination complex compound composed of an anion in whicha plurality of radicals are bonded to a metal and a cation, ormethylaluminoxane, and an alkylating agent as principal components, theuse of a reaction product between a straight-chain alkylaluminum havingat least two carbon atoms and water can lower the molecular weight ofthe resultant polymer without deteriorating the catalytic activity. Thepresent invention has been accomplished on the basis of theabove-mentioned finding and information.

SUMMARY OF THE INVENTION

Specifically, the present invention provides a process for producing astyrenic polymer which comprises polymerizing a styrenic monomer by theuse of (a) a transition metal compound, (b) a coordination complexcompound comprising an anion in which a plurality of radicals are bondedto a metal and a cation, or methylaluminoxane, (c) an alkylating agentand (d) a reaction product between a straight chain alkylaluminum havingat least two carbon atoms and water.

DESCRIPTION OF PREFERRED EMBODIMENT

As an (a) transition metal compound usable in the process of the presentinvention, mention may be made of a variety of compounds, usually thecompound represented by the general formula (I) or (II)

MR¹ _(a)R² _(b)R³ _(c)R⁴ _(4-(a+b+c))  (I)

MR¹ _(d)R² _(e)R³ _(3-(d+e))  (II)

wherein M is a metal belonging to any of the groups 3 to 6 of thePeriodic Table or a lanthanum series metal; R¹, R², R³ and R⁴ are eachan alkyl group, an alkoxyl group, an aryl group, a cyclopentadienylgroup, an alkylthio group, a substituted cyclopentadienyl group, anindenyl group, a substituted indenyl group, a fluorenyl group, a halogenatom or a chelating agent; a, b and c are each an integer of from 0 to4; d and e are each an integer of from 0 to 3; and any two of R¹ to R⁴may form a complex which is crosslinked with CH₂, Si(CH₃)₂ or the like.

As a metal belonging to any of the groups 3 to 6 of the Periodic Tableor a lanthanum series metal as indicated by M, there are preferablyemployed the group 4 metals, especially titanium, zirconium, hafnium andthe like.

Various titanium compounds can be used and a preferred example is atleast one compound selected from the group consisting of titaniumcompounds and titanium chelate compounds represented by the generalformula (III) or (IV):

TiR⁵ _(e)R⁶ _(f)R⁷ _(g)R⁸ _(4-(a+b+c))  (III)

TiR⁵ _(h)R⁶ _(i)R⁷ _(3-(d+e))  (IV)

wherein R⁵, R⁶, R⁷ and R⁸ are each a hydrogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an alkoxyl group having 1 to 20 carbonatoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, anarylalkyl group, an acyloxyl group having 1 to 20 carbon atoms, acyclopentadienyl group, a substituted cyclopentadienyl group, an indenylgroup, a substituted indenyl group, a fluorenyl group, an alkylthiogroup, an arylthio group, a chelating agent, an amino group, an amidegroup, a phosphorus-containing group or a halogen atom; a, b and c areeach an integer from 0 to 4; a and e are each an integer from 0 to 3;and any two of R⁵ to R⁸ may form a complex which is crosslinked withCH₂, Si(CH₃)₂ or the like.

R⁵, R⁶, R⁷ and R⁸ in the general formulae (III) and (IV) each representa hydrogen atom, an alkyl group having 1 to 20 carbon atoms(specifically, methyl group, ethyl group, propyl group, butyl group,amyl group, isoamyl group, isobutyl group, octyl group and 2-ethylhexylgroup), an alkoxyl group having 1 to 20 carbon atoms (specifically,methoxyl group, ethoxyl group, propoxyl group, butoxyl group, amyloxylgroup, hexyloxyl group, and 2-ethylhexyloxyl group), an aryl grouphaving 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group(specifically, phenyl group, tolyl group, xylyl group and benzyl group),an acyloxyl group having 1 to 20 carbon atoms (specifically,heptadecylcarbonyloxy group), a cyclopentadienyl group, a substitutedcyclopentadienyl group (specifically, methylcyclopentadienyl group,1,2-dimethylcyclopentadienyl group, pentamethylcyclopentadienyl groupand 4,5,6,7-tetrahydro-1,2,3-trimethylindenyl group), an indenyl group,a substituted indenyl group (specifically, methylindenyl group,dimethylindenyl group, tetramethylindenyl group and hexamethylindenylgroup), a fluorenyl group, (specifically, methylfluorenyl group,dimethylfluorenyl group, tetramethylfluorenyl group andoctamethylfluorenyl group), an alkylthio group (specifically, methylthiogroup, ethylthio group, butylthio group, amylthio group, isoamylthiogroup, isobutylthio group, octylthio group and 2-ethylhexylthio group),an arylthio group (specifically, phenylthio group, p-methylphenylthiogroup and p-methoxyphenylthio group), a chelating agent (specifically,2,21-thiobis (4-methyl-6-tert-butylphenyl) group, or a halogen atom(specifically, chlorine, bromine, iodine and fluorine). These R⁵, R⁶,R⁷, R⁸ may be the same as or different from each other.

More desirable titanium compounds include a titanium compoundrepresented by the formula (V)

TiRXYZ  (V)

wherein R represents a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group, afluorenyl group, or the like; X, Y, and Z, independently of one another,are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, analkoxyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20carbon atoms, an aryloxyl group having 6 to 20 carbon atoms, anarylalkyl group having 6 to 20 carbon atoms, an alkyl- or arylamidegroup having 1 to 40 carbon atoms or a halogen atom. Here, any one of X,Y and Z and R may form a compound which is crosslinked with CH₂, SiR₂ orthe like.

The substituted cyclopentadienyl group represented by R in the aboveformula is, for example, a cyclopentadienyl group substituted by atleast one of an alkyl group having 1 to 6 carbon atoms, morespecifically, methylcyclopentadienyl group, 1,2-dimethylcyclopentadienylgroup, 1,2,4-trimethylcyclopentadienyl group,1,2,3,4-tetramethylcyclopentadienyl group,trimethylsilylcyclopentadienyl group, 1,3-di(trimethylsilyl)cyclopentadienyl group, tert-butylcyclopentadienyl group,1,3-di(tert-butyl)cyclopentadienyl group, pentamethylcyclopentadienylgroup or the like. In addition, X, Y, and Z are each independently ahydrogen atom, an alkyl group having 1 to 12 carbon atoms (specifically,methyl group, ethyl group, propyl group, n-butyl group, isobutyl group,amyl group, isoamyl group, octyl group and 2-ethylhexyl group), analkoxyl group having 1 to 12 carbon atoms (specifically, methoxyl group,ethoxyl group, propoxyl group, butoxyl group, amyloxyl group, hexyloxylgroup, octyloxyl group and 2-ethylhexyloxyl group), an aryl group having6 to 20 carbon atoms (specifically, phenyl group and naphthyl group), anaryloxyl group having 6 to 20 carbon atoms (specifically, phenoxylgroup), an arylalkyl group having 6 to 20 carbon atoms (specifically,benzyl group), an alkyl- or arylamide group having 1 to 40 carbon atoms(specifically, dimethylamide group, diethylamide group, diphenylamidegroup and methylphenylamide group) or a halogen atom (specifically,chlorine, bromine, iodine and fluorine).

Specific examples of the titanium compound represented by the generalformula (V) include cyclopentadienyltrimethyltitanium,cyclopentadienyltriethyltitanium, cyclopentadienyltripropyltitanium,cyclopentadienyltributyltitanium,methylcyclopentadienyltrimethyltitanum,1,2-dimethylcyclopentadienyltrimethyltitanium,1,2,4-trimethylcyclopentadienyltrimethyltitanium,1,2,3,4-tetramethylcyclopentadienyltrimethyltitanium,pentamethylcyclopentadienyltrimethyltitanium,pentamethylcyclopentadienyltriethyltitanium,pentamethylcyclopentadienyltripropyltitanium,pentamethylcyclopentadienyltributyltitanium,cyclopentadienylmethyltitanium dichloride, cyclopentadienylethyltitaniumdichloride, pentamethylcyclopentadienylmethyltitanium dichloride,pentamethylcyclopentadienylethyltitanium dichloride,cyclopentadienyldimethyltitanium monochloride,cyclopentadienyldiethyltitanium monochloride, cyclopentadienyltitaniumtrimethoxide, cyclopentadienyltitanium triethoxide,cyclopentadienyltitanium tripropoxide, cyclopentadienyltitaniumtriphenoxide, pentamethylcyclopentadienyltitanium trimethoxide,pentamethylcyclopentadienyltitanium triethoxide,pentamethylcyclopentadienyltitanium tripropoxide,pentamethylcyclopentadienyltitanium tributoxide,pentamethylcyclopentadienyltitanium triphenoxide,cyclopentadienyltitanium trichloride,pentamethylcyclopentadienyltitanium trichloride,cyclopentadienylmethoxyltitanium dichloride,cyclopentadienyldimethoxytitanium chloride,pentamethylcyclopentadienylmethoxytitanium dichloride,cyclopentadienyltribenzyltitanium,pentamethylcyclopentadienylmethyldiethoxytitanium, indenyltitaniumtrichloride, indenyltitanium trimethoxide, indenyltitanium triethoxide,indenyltrimethyltitanium, indenyltribenzyltitanium,(tert-butylamide)dimethyl (tetramethylη⁵-cyclopentadienyl)silanetitanium dichloride,(tert-butylamide)dimethyl)tetramethyl η⁵-cyclopentadienyl)silanetitanium and (tert-butylamide)dimethyl(tetramethylη⁵-cyclopentadienyl)silanetitanium dimethoxide.

Of these titanium compounds, a compound not containing a halogen atom ispreferred and a titanium compound having one π electron type ligand isparticularly desirable.

Furthermore, a condensed titanium compound represented by the generalformula (VI) may be used as the titanium compound.

wherein R⁹ and R¹⁰ each represent a halogen atom, an alkoxyl grouphaving 1 to 20 carbon atoms or an acyloxyl group; and k is an integerfrom 2 to 20.

Furthermore, the above titanium compounds may be used in the form of acomplex formed with an ester, an ether or the like.

The trivalent titanium compound represented by the formula (VI)typically includes a trihalogenatd titanium such as titaniumtrichloride; and a cyclopentadienyltitanium compound such ascyclopentadienyltitanium dichloride, and also those obtained by reducinga tetravalent titanium compound. These trivalent titanium compounds maybe used in the form of a complex formed with an ester, an ether or thelike.

In addition, examples of the zirconium compound used as the transitionmetal compound include tetrabenzylzirconium, zirconium tetraethoxide,zirconium tetrabutoxide, bisindenylzirconium dichloride,triisopropoxyzirconium chloride, zirconium benzyldichloride andtributoxyzirconium chloride. Examples of the hafnium compound includetetrabenzylhafnium, hafnium tetraethoxide and hafnium tetrabutoxide.Examples of the vanadium compound include vanadyl bisacetylacetonato,vanadyl triacetylacetonato, vanadyl triethoxide and vanadyltripropoxide. Of these transition metal compounds, the titaniumcompounds are particularly suitable.

Aside from the foregoing, the transition metal compounds constitutingthe component (a) include the transition metal compound with two ligandshaving conjugated π electrons, for example, at least one compoundselected from the group consisting of the transition metal compoundsrepresented by the general formula:

M¹R¹¹R¹²R¹³R¹⁴  (VII)

wherein M¹ is titanium, zirconium or hafnium; R¹¹ and R¹² are each acyclopentadienyl group, substituted cyclopentadienyl group, indenylgroup or fluorenyl group and R¹³ and R¹⁴ are each a hydrogen atom, ahalogen atom, a hydrocarbon group having 1 to 20 carbon atoms, analkoxyl group having 1 to 20 carbon atoms, an amino group or thioalkoxylgroup having 1 to 20 carbon atoms, but R¹¹ and R¹² may be eachcrosslinked by a hydrocarbon group having 1 to 5 carbon atoms,alkylsilyl group having 1 to 20 carbon atoms and 1 to 5 silicon atoms orgermanium-containing hydrocarbon group having 1 to 20 carbon atoms and 1to 5 germanium atoms.

In more detail, each of R¹¹ and R¹² in the general formula (VII)designates a cyclopentadienyl group, substituted cyclopentadienyl group,more specifically, methylcyclopentadienyl group;1,3-dimethylcyclopentadienyl group; 1,2,4-trimethylcyclopentadienylgroup; 1,2,3,4-tetramethylcyclopentadienyl group;pentamethylcyclopentadienyl group; trimethylsilylcyclopentadienyl group;1,3-di(trimethylsilyl)cyclopentadienyl group;1,2,4-tri(trimethylsilyl)cyclopentadienyl group;tert-butylcyclopentadienyl group; 1,3-di(tert-butyl) cyclopentadienylgroup; 1,2,4-tri(tert-butyl) cyclopentadienyl group or the like, indenylgroup, substituted indenyl group, more specifically, methylindenylgroup; dimethylindenyl group; trimethylindenyl group or the like,fluorenyl group, or substituted fluorenyl group such as methylfluorenylgroup, and may be the same or different and crosslinked by an alkylidenegroup having 1 to 5 carbon atoms, more specifically, methine group;ethylidene group; propylidene group; dimethylcarbyl group or the like,or an alkylsilyl group having 1 to 20 carbon atoms and 1 to 5 siliconatoms, more specifically, dimethylsilyl group; diethylsilyl group;dibenzylsilyl group or the like. Each of R¹³ and R¹⁴ independentlyindicates, as described above but more specifically, a hydrogen atom; analkyl group having 1 to 20 carbon atoms such as methyl group, ethylgroup, propyl group, n-butyl group, isobutyl group, amyl group, isoamylgroup, octyl group or 2-ethylhexyl group; an aryl group having 6 to 20carbon atoms such as phenyl group or naphthyl group; an arylalkyl grouphaving 7 to 20 carbon atoms such as benzyl group; an alkoxyl grouphaving 1 to 20 carbon atoms such as methoxyl group, ethoxyl group,propoxyl group, butoxyl group, amyloxyl group, hexyloxyl group,octyloxyl group or 2-ethylhexyloxyl group; an aryloxyl group having 6 to20 carbon atoms such as phenoxyl group; an amino group; or a thioalkoxylgroup having 1 to 20 carbon atoms.

Specific examples of the transition metal compounds represented by thegeneral formula (VII) wherein M¹ is titanium includebis(cyclopentadienyl)dimethyltitanium;bis(cyclopentadienyl)diethyltitanium;bis(cyclopentadienyl)dipropyltitanium;bis(cyclopentadienyl)dibutyltitanium;bis(methylcyclopentadienyl)dimethyltitanium;bis(tert-butylcyclopentadienyl)dimethyltitanium;bis(1,3-dimethylcyclopentadienyl)dimethyltitanium;bis(1,3-di-tert-butylcyclopentadienyl)dimethyltitanium;bis(1,2,4-trimethylcyclopentadienyl)dimethyltitanium;bis(1,2,3,4-tetramethylcyclopentadienyl)dimethyltitanium;bis(cyclopentadienyl)dimethyltitanium;bis(trimethylsilylcyclopentadienyl)dimethyltitanium;bis(1,3-di(trimethylsilyl)cyclopentadienyl)dimethyltitanium;bis(1,2,4-tris(trimethylsilyl)cyclopentadienyl)dimethyltitanium;bis(indenyl)dimethyltitanium; bis(fluorenyl)dimethyltitanium;methylenebis(cyclopentadienyl)dimethyltitanium;ethylidenebis(cyclopentadienyl)dimethyltitanium;methylenebis(2,3,4,5-tetramethylcyclopentadienyl)dimethyltitanium;ethylidenebis(2,3,4,5-tetramethylcyclopentadienyl)dimethyltitanium;dimethylsilylbis(2,3,4,5-tetramethylcyclopentadienyl)dimethyltitanium;methylenebisindenyldimethyltitanium;ethylidenebisindenyldimethyltitanium;dimethylsilylbisindenyldimethyltitanium;methylenebisfluorenyldimethyltitanium;ethylidenebisfluorenyldimethyltitanium;dimethylsilylbisfluorenyldimethyltitanium;methylene(tert-butylcyclopentadienyl)(cyclopentadienyl)dimethyltitanium;methylene(cyclopentadienyl)(indenyl)dimethyltitanium;ethylidene(cyclopentadienyl)(indenyl)dimethyltitanium;dimethylsilyl(cyclopentadienyl)(indenyl)dimethyltitanium;methylene(cyclopentadienyl)(fluorenyl)dimethyltitanium;ethylidene(cyclopentadienyl)(fluorenyl)dimethyltitanium;dimethylsilyl(cyclopentadienyl)(fluorenyl)dimethyltitanium;methylene(indenyl)(fluorenyl)dimethyltitanium;ethylidene(indenyl)(fluorenyl)dimethyltitanium;dimethylsilyl(indenyl)(fluorenyl)dimethyltitanium;bis(cyclopentadienyl)dibenzyltitanium;bis(tert-butylcyclopentadienyl)dibenzyltitanium;bis(methylcyclopentadienyl)dibenzyltitanium;bis(1,3-dimethylcyclopentadienyl)dibenzyltitanium;bis(1,2,4-trimethylcyclopentadienyl)dibenzyltitanium;bis(1,2,3,4-tetramethylcyclopentadienyl)dibenzyltitanium;bis(pentamethylcyclopentadienyl)dibenzyltitanium;bis(trimethylsilylcyclopentadienyl)dibenzyltitanium;bis[1,3-di-(trimethylsilyl)cyclopentadienyl]dibenzyltitanium;bis[1,2,4-tris(trimethylsilyl)cyclopentadienyl]dibenzyltitanium;bis(indenyl)dibenzyltitanium; bis(fluorenyl)dibenzyltitanium;methylenebis(cyclopentadienyl)dibenzyltitanium;ethylidenebis(cyclopentadienyl)dibenzyltitanium;methylenebis(2,3,4,5-tetramethylcyclopentadienyl)dibenzyltitanium;ethylidenebis(2,3,4,5-tetramethylcyclopentadienyl)dibenzyltitanium;dimethylsilylbis(2,3,4,5-tetramethylcyclopentadienyl)dibenzyltitanium;methylenebis(indenyl)dibenzyltitanium;ethylidenebis(indenyl)dibenzyltitanium;dimethylsilylbis(indenyl)dibenzyltitanium;methylenebis(fluorenyl)dibenzyltitanium;ethylidenebis(fluorenyl)dibenzyltitanium;dimethylsilylbis(fluorenyl)dibenzyltitanium;methylene(cyclopentadienyl)(indenyl)dibenzyltitanium;ethylidene(cyclopentadienyl)(indenyl)dibenzyltitanium;dimethylsilyl(cyclopentadienyl)(indenyl)dibenzyltitanium;methylene(cyclopentadienyl)(fluorenyl)dibenzyltitanium;ethylidene(cyclopentadienyl)(fluorenyl)dibenzyltitanium;dimethylsilyl(cyclopentadienyl)(fluorenyl)dibenzyltitanium;methylene(indenyl)(fluorenyl)dibenzyltitanium;ethylidene(indenyl)(fluorenyl)dibenzyltitanium;dimethylsilyl(indenyl)(fluorenyl)dibenzyltitanium;biscyclopentadienyltitanium dimethoxide; biscyclopentadienyltitaniumdiethoxide; biscyclopentadienyltitanium dipropoxide;biscyclopentadienyltitanium dibutoxide; biscyclopentadienyltitaniumdipheoxide; bis(methylcyclopentadienyl)titanium dimethoxide;bis(1,3-dimethylcyclopentadienyl)titanium dimethoxide;bis(1,2,4-trimethylcyclopentadienyl)titanium dimethoxide;bis(1,2,3,4-tetramethylcyclopentadienyl)titanium dimethoxide;bispentamethylcyclopentadienyltitanium dimethoxide;bis(trimethylsilylcyclopentadienyl)titanium dimethoxide;bis[1,3-di(trimethylsilyl)cyclopentadienyl]titanium dimethoxide; bis[1,2,4-tri(trimethylsilyl)cyclopentadienyl]titanium dimethoxide;bisindenyltitanium dimethoxide; bisfluorenyltitanium dimethoxide;methylenebiscyclopentadienyltitanium dimethoxide;ethylidenebiscyclopentadienyltitanium dimethoxide;methylenebis(2,3,4,5-tetramethylcyclopentadienyl)titanium dimethoxide;ethylidenebis(2,3,4,5-tetramethylcyclopentadienyl)titanium dimethoxide;dimethylsilylenebis(2,3,4,5-tetramethylcyclopentadienyl)titaniumdimethoxide; methylenebisindenyltitanium dimethoxide;methylenebis(methylindenyl)titanium dimethoxide;ethylidenebisindenyltitanium dimethoxide;dimethylsilylbisindenyltitanium dimethoxide;methylenebisfluorenyltitanium dimethoxide;methylenebis(methylfluorenyl)titanium dimethoxide;ethylidenebisfluorenyltitanium dimethoxide;dimethylsilylbisfluorenyltitanium dimethoxide; methylene(cyclopentadienyl)(indenyl)titanium dimethoxide;ethylidene(cyclopentadienyl)(indenyl)titanium dimethoxide;dimethylsilyl(cyclopentadienyl)(indenyl)titanium dimethoxide;methylene(cyclopentadienyl)(fluorenyl)titanium dimethoxide;ethylidene(cyclopentadienyl)(fluorenyl)titanium dimethoxide;dimethylsilyl(cyclopentadienyl)(fluorenyl)titanium dimethoxide;methylene(indenyl)(fluorenyl)titanium dimethoxide;ethylidene(indenyl)(fluorenyl)titanium dimethoxide; anddimethylsilyl(indenyl)(fluorenyl)titanium dimethoxide.

Examples of the transition metal compounds represented by the formula(VII) wherein M¹ is zirconium includeethylidenebiscyclopentadienylzirconium dimethoxide anddimethylsilylbiscyclopentadienylzirconium dimethoxide. Examples of thehafnium compounds according to the general formula (VII) includeethylidenebiscyclopentadienylhafnium dimethoxide,dimethylsilylbiscyclopentadienylhafnium dimethoxide, etc. Particularlydesirable transition metal compounds among them are titanium compounds.In addition to the combinations of the above, the compound may be abidentate coordination complex compound such as2,2′-thiobis-(4-methyl-6-tert-butylphenyl)titanium diisopropoxide;2,2′-thiobis(4-methyl-6-tert-butylphenyl)titanium dimethoxide or thelike.

As the transition metal compound of the component (a) usable in thepresent invention, there is available at least one compound selectedfrom the group consisting of the transition metal compounds having theconstitution represented by the general formula (VIII)

R′MX′_(p-1)L¹ _(q)  (VIII)

wherein R is, as a π ligand, a fused polycyclic cyclopentadienyl groupwherein at least one of many-membered rings to which cyclopentadienylgroups are fusedly bonded is a saturated ring, M is as previouslydefined, X′ is a σ ligand, a plurality of X′ may be the same ordifferent and bonded to each other through an arbitrary group, L¹ is aLewis base, p is the valency of M, q is 0, 1 or 2 and when L¹ is plural,each L¹ may be the same or different. The above-mentioned fusedpolycyclic cyclopentadienyl group is exemplified by that selected fromthose represented by any one of the general formulae (IX) to (XI)

wherein R¹⁵, R¹⁶ and R¹⁷ are each a hydrogen atom, a hydrogen atom, ahalogen atom, an aliphatic hydrocarbon group having 1 to 20 carbonatoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, analkoxyl group having 1 to 20 carbon atoms, an aryloxyl group having 6 to20 carbon atoms, a thioalkoxyl group having 1 to 20 carbon atoms, athioaryloxyl group having 6 to 20 carbon atoms, an amino group, an amidegroup, a carboxyl group or an alkylsilyl group and may be the same as ordifferent from each other; and w, x, y and z are each an integer of 1 orgreater. Of these, 4,5,6,7-tetrahydroindenyl group is preferable fromthe viewpoint of catalytic activity and the ease of its synthesis.

Specific examples of R′ include 4,5,6,7-tetrahydroindenyl group;1-methyl-4,5,6,7-tetrahydroindenyl group;2-methyl-4,5,6,7-tetrahydroindenyl group;1,2-dimethyl-4,5,6,7-tetrahydroindenyl group;1,3-dimethyl-4,5,6,7-tetrahydroindenyl group;1,2,3-trimethyl-4,5,6,7-tetrahydroindenyl group;1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyl group;1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyl group;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyl group;octahydrofluorenyl group; 1,2,3,4-tetrahydrofluorenyl group;9-methyl-1,2,3,4-tetrahydrofluorenyl group; and9-methyl-octahydrofluorenyl group.

M is a Group 3 to 6 metal or a lanthanoids metal and exemplified bytitanium, zirconium, hafnium, lanthanoids, niobium and tantalum. Ofthese titanium is preferable from the viewpoint of catalytic activity.X′ is a σ ligand and is exemplified by a hydrogen atom, a halogen atom,an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatichydrocarbon group having 6 to 20 carbon atoms, an alkoxyl group having 1to 20 carbon atoms, an aryloxyl group having 6 to 20 carbon atoms, athioalkoxyl group having 1 to 20 carbon atoms, a thioaryloxyl grouphaving 6 to 20 carbon atoms, an amino group, an amide group, a carboxylgroup or an alkylsilyl group, and a plurality of X′ may be the same ordifferent and bonded to each other through an arbitrary group. Further,X′ is specifically exemplified by hydrogen atom, chlorine atom, bromineatom, iodine atom, methyl group, benzyl group, phenyl group,trimethylsilylmethyl group, methoxy group, ethoxy group, phenoxy group,thiomethoxy group, thiophenoxy group, dimethylamino group anddiisopropylamino group. L¹ is a Lewis base, p is the valency of M and qis 0, 1 or 2.

As the transition metal compound represented by the general formula(VIII), there can preferably be employed a compound comprising R′ and X′each arbitrarily selected from the above-exemplified groups.

The transition metal compound represented by the general formula (I) isspecifically exemplified by but not limited to4,5,6,7-tetrahydroindenyltitanium trichloride;4,5,6,7-tetrahydroindenyltrimethyltitanium;4,5,6,7-tetrahydroindenyltribenzyltitanium;4,5,6,7-tetrahydroindenyltitanium trimethoxide;1-methyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1-methyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1-methyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1-methyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;2-methyl-4,5,6,7-tetrahydroindenyltitanium trichloride;2-methyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;2-methyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;2-methyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;1,2-dimethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,2-dimethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,2-dimethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,2-dimethyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;1,3-dimethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,3-dimethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,3-dimethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,3-dimethyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;1,2,3-trimethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,2,3-trimethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,2,3-trimethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,2,3-trimethyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,2,3,4,5,6,7-heptamethyl-4,5,6,7-tetrahydroindenyltitaniumtrimethoxide; 1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltitaniumtrichloride;1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,2,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltitanium trichloride;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltrimethyltitanium;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltribenzyltitanium;1,3,4,5,6,7-hexamethyl-4,5,6,7-tetrahydroindenyltitanium trimethoxide;octahydrofluorenyltitanium trichloride;octahydrofluorenyltrimethyltitanium;octahydrofluorenyltribenzyltitanium; octahydrofluorenyltitaniumtrimethoxide; 1,2,3,4-tetrahydrofluorenyltitanium trichloride;1,2,3,4-tetrahydrofluorenyltrimethyltitanium;1,2,3,4-tetrahydrofluorenyltribenzyltitanium;1,2,3,4-tetrahydrofluorenyltitanium trimethoxide;9-methyl-1,2,3,4-tetrahydrofluorenyltitanium trichloride;9-methyl-1,2,3,4-tetrahydrofluorenyltrimethyltitanium;9-methyl-1,2,3,4-tetrahydrofluorenyltribenzyltitanium;9-methyl-1,2,3,4-tetrahydrofluorenyltitanium trimethoxide;9-methyloctahydrofluorenyltitanium trichloride;9-methyloctahydrofluorenyltrimethyltitanium;9-methyloctahydrofluorenyltribenzyltitanium;9-methyloctahydrofluorenyltitanium trimethoxide; any of theabove-mentioned compounds in which the titanium is replaced withzirconium or hafnium and a similar compound in which the transitionmetal element belongs to an other series or lanthnoids. Of these thetitanium compounds are preferable from the viewpoint of catalyticactivity.

There are available various coordination complex compounds comprising ananion in which a plurality of radicals are bonded to a metal to be usedas the component (b) in the present invention, and there is preferablyusable such a coordination complex compound as represented by thefollowing general formula (XII) or (XIII):

([L¹−H]^(g+))_(h)([M²X¹X² - - - X^(n)]^((n-m)-))_(i)  (XII)

or

([L²]^(g+))_(q)([M³X¹X² - - - X^(n)]^((n-m)-))_(i)  (XIII)

wherein L² is M⁴, R¹⁸R¹⁹M⁵ or R²⁰ ₃C as hereinafter described; L₁ is aLewis base; M² and M³ are each a metal selected from Groups 5 to 15 ofthe Periodic Table; M⁴ is a metal selected from Groups 8 to 12 of thePeriodic Table; M⁵ is a metal selected from Groups 8 to 10 of thePeriodic Table; X¹ to X^(n) are each a hydrogen atom, a dialkylaminogroup, an alkoxyl group, an aryloxyl group, an alkyl group having 1 to20 carbon atoms, an aryl group, an alkylaryl group or an arylalkylgroup, each having 6 to 20 carbon atoms, a substituted alkyl group, anorganometalloid group or a halogen atom; R¹⁸ and R¹⁹ are each acyclopentadienyl group, a substituted cyclopentadienyl group, an indenylgroup or a fluorenyl group; R²⁰ is an alkyl group; m is the valency ofeach of M² and M³, indicating an integer of 1 to 7; n is an integer of 2to 8; g is the ion valency of each of [L¹−H] and [L²], indicating aninteger of 1 to 7; h is an integer of 1 or more; and j=h×g/(n-m).

Specific examples of M² and M³ include B, Al, Si, P, As, Sb, etc. in theform of atom; those of M⁴ include Ag, Cu, etc. in the form of atom; andthose of M⁵ include Fe, Co, Ni, etc. in the form of atom. Specificexamples of X¹ to X^(n) include a dialkylamino group such asdimethylamino and diethylamino; an alkoxyl group such as methoxyl,ethoxyl and n-butoxyl; an aryloxyl group such as phenoxyl,2,6-dimethylphenoxyl and naphthyloxyl; an alkyl group having 1 to 20carbon atoms such as methyl, ethyl, n-propyl, iso-propyl, n-butyl,n-octyl and 2-ethylhexyl; an aryl group, an alkylaryl group or anarylalkyl group each having 6 to 20 carbon atoms, such as phenyl,p-tolyl, benzyl, pentafluorophenyl, 3,5-di(trifluoromethyl)phenyl,4-tertbutylphenyl, 2,6-dimethylphenyl, 3,5-dimethylphenyl,2,4dimethylphenyl and 1,2-dimethylphenyl; a halogen atom such as F, Cl,Br and I; and an organometalloid such as pentamethylantimony group,trimethylsilyl group, trimethylgermyl group, diphenylarsine group,dicyclohexylantimony group and diphenylboron group. Specific examples ofsubstituted cyclopentadienyl group represented by any of R¹⁸ and R¹⁹include methylcyclopentadienyl, butylcyclopentadienyl andpentamethylcyclopentadienyl.

Specific examples of the anion in which a plurality of radicals arebonded to a metal include B(C₆F₅)₄ ⁻, B(C₆HF₄)₄ ⁻, B(C₆H₂F₃)₄ ⁻,B(C₆H₃F₂)₄ ⁻, B(C₆H₄F)₄ ⁻, B(C₆CF₃F₄)₄ ⁻, B(C₆F₅)₄ ⁻, BF₄ ⁻, PF₆ ⁻,P(C₆F₅)₆ ⁻ and Al(C₆HF₄)₄−.

Specific examples of the metallic cation include CpFe⁺, (MeCp)₂Fe⁺,(tBuCp)₂Fe⁺, (Me₂Cp)₂Fe⁺, (Me₃CP)₂Fe⁺, (Me₄Cp)₂Fe⁺, (Me₅Cp)₂Fe⁺, Ag⁺,Na⁺ and Li⁺, a nitrogen atom-containing compound such as pyridinium,2,4-dinitro-N,N-diethylanilinium, diphenylammonium, p-nitroanilinium,2,5-dichloroaniline, p-nitro-N,N-dimethylanilinum, quinolinium,N,N-dimethylanilinum and N,N-diethylanilinium; a carbenium compound suchas triphenylcarbenium, tri(4-methylphenyl)carbenium andtri(4-methoxyphenyl)carbenium; an alkylphosphonium ion such as CH₃PH₃ ⁺,C₂H₅PH₃ ⁺, C₃H₇PH₃ ⁺, (CH₃)₂PH₂ ⁺, (C₂H₅)₂PH₂ ⁺, (C₃H₇)₂PH₂ ⁺,(CH₃)₃PH⁺, (C₂H₅)₃PH⁺, (C₃H₇)₃PH⁺, (CF₃)₃PH⁺, (CH₃)₄P⁺, (C₂H₅)₄P⁺ and(C₃H₇)₄P⁺; and an arylphosphonium ion such as C₆H₅PH₃ ⁺, (C₆H₅)₂PH₂ ⁺,(C₆H₅)₃PH⁺, (C₆H₅)₄P⁺, (C₂H₅)₂(C₆H₅)PH⁺, (CH₃)(C₆H₅)PH₂ ⁺,(CH₃)₂(C₆H₅)PH⁺ and (C₂H₅)₂(C₆H₅)₂P⁺.

Among the compounds represented by the general formula (XII) or (XIII),specific examples of preferably usable compounds include, as thecompound of the general formula (XII), triethylammoniumtetraphenylborate, tri(n-butyl) ammonium tetraphenylborate,trimethylammonium tetraphenylborate, triethylammoniumtetra(pentafluorophenyl)borate, tri(n-butyl)ammoniumtetra(pentafluorophenyl)borate, triethylammonium hexafluoroarsenate,pyridinium tetra(pentafluorophenyl))borate, pyrroliniumtetra(pentafluorophenyl)borate, N,N-dimethylaniliniumtetra(pentafluorophenyl)borate and methyldiphenylammoniumtetra(pentafluorophenyl)borate, and as the compound of the generalformula (XIII), ferrocenium tetraphenylborate, dimethylferroceniumtetra(pentafluorophenyl)borate, ferroceniumtetra(pentafluorophenyl)borate, decamethylferroceniumtetra(pentafluorophenyl)borate, acetylferroceniumtetra(pentafluorophenyl)borate, formylferroceniumtetra(pentafluorophenyl)borate, cyanoferroceniumtetra(pentafluorophenyl)borate, silver tetraphenylborate, silvertetra(pentafluorophenyl)borate, trityl tetraphenylborate, trityltetra(pentafluorophenyl)borate, silver hexafluoroarsenate, silverhexafluoroantimonate and silver tetrafluoroborate.

Methylaluminoxane may be used as the component (b) in addition to or inplace of the coordination complex compound comprising an anion in whicha plurality of radicals are bonded to a metal and a cation.

There are available various alkylating agents as the component (c),which are exemplified by the aluminum compound having an alkyl grouprepresented by the general formula (XV)

R²¹ _(m′)Al (OR²²)_(n′)X_(3-m′-n′)  (XV)

wherein R²¹ and R²² are each an alkyl group having 1 to 8, preferably 1to 4 carbon atoms, X is a hydrogen atom or a halogen atom, m′ satisfiesthe relation 0<m′≦3, desirably m′=2 or 3, most desirably m′=3, and n′satisfies the relation 0≦n′<3, desirably n′=0 or 1; the magnesiumcompound having an alkyl group represented by the general formula (XVI)

R²¹ ₂Mg  (XVI)

wherein R²¹ is as previously defined;

the zinc compound having an alkyl group represented by the generalformula (XVII)

R²¹ ₂Zn  (XVII)

wherein R²¹ is as previously defined; and the like.

The aforesaid compounds each having an alkyl group are preferablyaluminum compounds each having an alkyl group, more desirablytrialkylaluminum compounds and dialkylaluminum compounds, andspecifically exemplified by trialkylaluminum such as trimethylaluminum,triethylaluminum, tri-n-propylaluminum, triisopropylaluminum,tri-n-butylaluminum, triisobutylaluminum and tri-tert-butylaluminum;dialkylaluminum halide such as dimethylaluminum chloride,diethylaluminum chloride, di-n-propylaluminum chloride,diisopropylaluminum chloride, di-n-butylaluminum chloride,diisobutylaluminum chloride and di-tert-butylaluminum chloride;dialkylaluminum alkoxide such as dimethylaluminum methoxide anddimethylaluminum ethoxide; dialkylaluminum hydride such asdimethylaluminum hydride, diethylaluminum hydride and diisobutylaluminumhydride, dialkylmagnesium such as dimethylmagnesium, diethylmagnesium,di-n-propylmagnesium and diisopropylmagnesium; and dialkylzinc such asdimethylzinc, diethylzinc, di-n-propylethylzinc and diisopropylzinc, andthe like.

As described hereinbefore, the process according to the presentinvention comprises polymerizing a styrenic monomer by the use of thecatalyst composed of the components (a), (b) and (c) and incorporatingin the polymerization system, a (d) reaction product between a straightchain alkylaluminum having at least two carbon atoms in the alkyl groupas represented by the general formula (XVIII) and water.

R^(o) ₃Al  (XVIII)

wherein R^(o) is a straight chain alkyl group having 2 to 10, preferably2 to 6 carbon atoms. Specific examples of such alkylaluminum includetriethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,tri-n-pentylaluminum, tri-n-hexylaluminum and tri-n-heptylaluminum.

The water to be reacted with the straight chain alkylaluminum may be anyof ice, water, steam, an organic solvent saturated with water and waterof crystallization.

The reaction product between such a straight chain alkylaluminum andwater to be used in the present invention is obtained by reacting theabove-mentioned straight chain alkylaluminum with water in a molar ratioof 1:(1 to 2) at a temperature of −78° to 100° C. in a organic solventwithout active hydrogen atom, and is represented by the general formula(XIX) or (XX)

wherein R^(o) is as previously defined and n is an integer from 1 to 20.Specific examples of these compounds include ethylaluminoxane,propylaluminoxane, butylaluminoxane, pentylaluminoxane, hexylaluminoxaneand heptylaluminoxane.

The above-mentioned compound represented by the general formula (XIX) or(XX) has preferably n of 1 to 5 and may be used alone or in combinationwith at least one other one.

In the case of carrying out the process of the present invention, theaforesaid components (a), (b), (c) and (d) may be added, separately oneby one, to the monomer to be polymerized, or may be premixed with asolvent (aromatic hydrocarbon such as toluene, and ethylbenzene oraliphatic hydrocarbon such as hexane and heptane) prior to mixing withthe monomer, in which the components (c) and (d) may totally or partlybe added to the monomer.

The addition of the aforesaid components (a), (b), (c) and (d) to themonomer can be carried out at a temperature of 0° to 100° C., needlessto say, at a polymerization temperature.

The above-described catalyst along with the chain transfer agent exhibita high activity in the production of a styrenic polymer having a highdegree of syndiotactic configuration.

The molecular weight of the resultant polymer can be lowered by theaddition of the component (d), but the amount thereof to be added is notspecifically limited, since it varies depending on the type of each ofthe components (a), (b), (c) and (d), the monomer species andpolymerization conditions such as polymerization temperature.

In the production of a styrenic polymer by the process according to thepresent invention, a styrenic monomer or monomers or a styrenicderivative or derivatives is homopolymerized or are copolymerized in thepresent of a catalyst composed mainly of the components (a), (b) and (c)and chain transfer agent of the component (d).

As the styrenic monomer, there is preferably used a compound representedby the general formula (XXI)

wherein R²³ is hydrogen atom, a halogen atom or a hydrocarbon grouphaving 1 to 20 carbon atoms, m′ is an integer from 1 to 3 and, when m′is 2 or greater, a plurality of R²³ may be the same or different.

Examples of the compound of the general formula (XXI) include styrene;alkylstyrenes such as p-methylstyrene; m-methylstyrene; o-methylstyrene;2,4-dimethylstyrene; 2,5-dimethylstyrene; 3,4-dimethylstyrene;3,5-dimethylstyrene; and p-tertiary-butylstyrene; polyvinylbenzenes suchas p-divinylbenzene; m-divinylbenzene; and trivinylbenzene; halogenatedstyrenes such as p-chlorostyrene; m-chlorostyrene; o-chlorostyrene;p-bromostyrene; m-bromostyrene; o-bromostyrene; p-fluorostyrene;m-fluorostyrene; o-fluorostyrene and o-methyl-p-fluorostyrene;alkoxystyrenes such as methoxystyrene; ethoxystyrene; andtert-butyoxystyrene; and a mixture of at least two of them.

The polymerization of the styrenic monomer or monomers may be carriedout by means of bulk polymerization or solution polymerization by theuse of an aliphatic hydrocarbon solvent such as pentane, hexane orheptane, an alicyclic hydrocarbon solvent such as cyclohexane or anaromatic hydrocarbon solvent such as benzene, toluene or xylene. Thepolymerization temperature is not specifically limited, but is usuallyin the range of 20° to 120° C., preferably 20° to 90° C. In addition,the polymerization reaction may be carried out in the presence ofhydrogen in order to modify the molecular weight of the styrenic polymerto be produced.

The styrenic polymer thus obtained possesses a high degree ofsyndiotactic configuration in its polymerization chain of the styrenicmonomer. Here, the styrenic polymer having a high degree of syndiotacticconfiguration in its polymerization chain of the styrenic monomer meansthat its stereochemical structure is mainly of syndiotacticconfiguration, i.e. the stereostructure in which phenyl groups orsubstituted phenyl group as side chains are located alternately atopposite directions relative to the main chain consisting ofcarbon-carbon bonds. Tacticity is quantitatively determined by thenuclear magnetic resonance method (¹³C-NMR method) using carbon isotope.The tacticity as determined by the ¹³C-NMR method can be indicated interms of proportions of structural units continuously connected to eachother, i.e., a diad in which two structural units are connected to eachother, a triad in which three structural units are connected to eachother and a pentad in which five structural unit are connected to eachother. “-The styrenic polymers having a high degree of syndiotacticconfiguration” as mentioned in the present invention means polystyrene,poly(alkylstyrene), poly(halogenated styrene), poly(alkoxystyrene),poly(vinylbenzoate), the mixtures thereof, and copolymers containing theabove polymers as main components, having such a syndiotacticity thatthe proportion of racemic diad is at least 75%, preferably at least 85%,or the proportion of racemic pentad is at least 30%, preferably at least50%. The poly(alkylstyrene) includes poly(methylstyrene),poly(ethylstyrene) poly(isopropylstyrene), poly(tert-butylstyrene),etc., poly(halogenated styrene) includes poly(chlorostyrene),poly(bromostyrene), and poly(fluorostyrene), etc. Thepoly(alkoxystyrene) includes poly(methoxystyrene), poly(ethoxystyrene),etc. The most desirable styrenic polymers are polystyrene,poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene),poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene), andthe copolymer of styrene and p-methylstyrene.

As described hereinbefore, the process according to the presentinvention makes it possible to attain a high activity in the productionof a styrenic polymer having a high degree of syndiotacticconfiguration, decrease the amount of the residual metals in theresultant styrenic polymer without deterioration of the catalyticactivity by the use of a reaction product between the specific straightchain alkylaluminum and water, and at the same time, to simplify theproduction process of the styrenic polymer and curtail the productioncost thereof.

In the following, the present invention will be described in more detailwith reference to comparative examples and examples, which however,shall not be construed to limit the present invention thereto.

EXAMPLE 1

(1) Synthesis of ethylaluminoxane

In a 5 liter (hereinafter abbreviated to “L”) vessel which had beendried and purged with nitrogen was placed 178 milliliter (hereinafterabbreviated to “mL”) of 0.5 mol/L solution of triethylaluminum in 112 mLof toluene. To the resultant mixture was gradually added dropwise undersufficient stirring at room temperature, 1.67 L solution in toluene(H₂O; 430.7×10⁻⁶ g/mL) which had been adjusted in water content by meansof ion-exchanged water. After the completion of the dropwise addition,the toluene was distilled away to form 8.5 g of product.

(2) Polymerization of styrene

In a 50 mL vessel which had been dried and purged with nitrogen weresuccessively placed 0.4 mL of 2 moles/L of triisobutylaluminum in 39.3mL of toluene, 64 mg of dimethylaniliniumtetra(pentafluorophenyl)borate, and 0.32 mL of 250 mmol ofpentamethylcyclopentadienyltitanium trimethoxide to prepare apreliminary mixed catalyst. In a 30 mL vessel which had been dried andpurged with nitrogen were placed 10 mL of styrene and 45 μL of 0.28mol/L of ethylaluminoxane with heating to 70° C. and 250 μL of thepreliminary mixed catalyst as prepared above to polymerize the styrenefor 1 hour. After the completion of the reaction, the reaction productwas dried to afford 2.99 g of a polymer. The resultant polymer was cutinto slices of at most 1 mm in thickness, which were subjected toSoxhlet extraction for 6 hours by the use of methyl ethyl ketone (MEK)as the solvent to produce MIP (MEK-insoluble portion). As a result,objective SPS having a molecular weight of 310,000 was obtained in ayield of 2.83 g with a raffinate (MIP) rate of 94.8% and an activity forSPS of 118 kg/g-Ti.

EXAMPLE 2

The procedure in Example 1 (2) was repeated to obtain 2.87 g of apolymer except that the addition amount of 0.28 mol/L ofethylaluminoxane was set on 90 μL in place of 45 μL. The resultantpolymer was subjected to Soxhlet extraction for 6 hours by the use ofmethyl ethyl ketone (MEK) as the solvent to produce MIP. As a result,objective SPS having a molecular weight of 240,000 was obtained in ayield of 2.80 g with a raffinate (MIP) rate of 97.6% and an activity forSPS of 117 kg/g-Ti.

EXAMPLE 3

The procedure in Example 1 (2) was repeated to obtain 2.87 g of apolymer except that there was used n-butylaluminoxane which had beenprepared in the same manner as in Example 1 (1) in place ofethylaluminoxane. The resultant polymer was subjected to Soxhletextraction for 6 hours by the use of methyl ethyl ketone (MEK) as thesolvent to produce MIP. As a result, objective SPS having a molecularweight of 350,000 was obtained in a yield of 2.81 g with a raffinate(MIP) rate of 97.9% and an activity for SPS of 117 kg/g-Ti.

EXAMPLE 4

The procedure in Example 1 (2) was repeated to obtain a polymer exceptthat there was used n-propylaluminoxane which had been prepared in thesame manner as in Example 1 (1) in place of ethylaluminoxane. Theresultant polymer was subjected to Soxhlet extraction for 6 hours by theuse of methyl ethyl ketone (MEK) as the solvent to produce MIP. As aresult, objective SPS having a molecular weight of 340,000 was obtainedwith a raffinate (MIP) rate of 95% and an activity for SPS of 120kg/g-Ti.

EXAMPLE 5

The procedure in Example 1 (2) was repeated to obtain a polymer exceptthat there was used ferrocenium tetra(pentafluorenyl)borate in place ofdimethylanilinium tetra(pentafluorenyl)borate. The resultant polymer wassubjected to Soxhlet extraction for 6 hours by the use of methyl ethylketone (MEK) as the solvent to produce MIP. As a result, objective SPShaving a molecular weight of 320,000 was obtained with a raffinate (MIP)rate of 95% and an activity for SPS of 122 kg/g-Ti.

EXAMPLE 6

The procedure in Example 1 (2) was repeated to obtain a polymer exceptthat there was used tri-n-butylaluminum in place of triisobutylaluminum.The resultant polymer was subjected to Soxhlet extraction for 6 hours bythe use of methyl ethyl ketone (MEK) as the solvent to produce MIP. As aresult, objective SPS having a molecular weight of 310,000 was obtainedwith a raffinate (MIP) rate of 95% and an activity for SPS of 119kg/g-Ti.

Comparative Example 1

The procedure in Example 1 (2) was repeated to obtain a polymer exceptthat ethylaluminoxane was not used. The resultant polymer was subjectedto Soxhlet extraction for 6 hours by the use of methyl ethyl ketone(MEK) as the solvent to produce MIP. As a result, objective SPS having amolecular weight of 871,000 was obtained in a yield of 2.69 g with araffinate (MIP) rate of 95.5% and an activity for SPS of 112 kg/g-Ti.

Example A

The procedure in Example 1 (2) was repeated except that 4.0 mL of 1.6mol/L of methylaluminoxane solution was used in place of 64 mg ofdimethylanilinium tetra(pentafluorophenyl)borate. As a result, objectiveSPS having a molecular weight of 340,000 was obtained in a yield of 3.25g with a raffinate (MIP) rate of 96.4% and an activity for SPS of 138kg/g-Ti.

Example B

The procedure in Example 1 (2) was repeated except that 0.5 mmol ofbutylethylmagnesium was used in place of 0.4 mL of 2 mol/L oftriisobutylaluminum and 4.0 mL of 1.6 mol/L of methylaluminoxanesolution was used in place of 64 mg of dimethylaniliniumtetra(pentafluorophenyl)borate. As a result, object SPS having amolecular weight of 370,000 was obtained in a yield of 2.25 g with araffinate (MIP) rate of 94.4% and an activity for SPS of 93 kg/g-Ti.

Comparative Example A

The procedure in Example 1 (2) was repeated except that 1.0 mL of 2.0mol/L of trimethylaluminum solution was used in place of 64 mg ofdimethylanilinium tetra(pentafluorophenyl)borate. As a result, objectiveSPS having a molecular weight of 270,000 was obtained in a yield of 0.95g with a raffinate (MIP) rate of 90.5% and an activity for SPS of 38kg/g-Ti.

What is claimed is:
 1. A process for producing a styrenic polymer havinga high degree of syndiotacticity, which comprises: polymerizing astyrenic monomer in the presence of a catalyst of (a) a transition metalcompound, (b) methylaluminoxane, (c) at least one alkylating agentselected from the group consisting of triethylaluminum,tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-tert-butylaluminum, dialkylaluminumhalide,dialkylmagnesium and dialkylzinc, and (d) a reaction product between astraight-chain alkylaluminum having at least 2 carbon atoms in the alkylgroup as represented by formula (XVIII) and water: R^(o) ₃Al  (XVIII)wherein R^(o) is a straight-chain alkyl group having 2 to 10 carbonatoms.
 2. The process according to claim 1 wherein the reaction productas the component (d) is a compound represented by formula

wherein R^(o) is a straight-chain alkyl group having 2 to 10 carbonatoms and n is an integer of 1 to
 20. 3. The process according to claim1 wherein the reaction product as the component (d) is at least onemember selected from the group consisting of ethylaluminoxane,propylaluminoxane, butylaluminoxane, pentylaluminoxane, hexylaluminoxaneand heptylaluminoxane.
 4. The process according to claim 1, wherein (a)said transition metal compound is of formula (I), (II), (VI) or (VII):MR¹ _(a)R² _(b)R³ _(c)R⁴ _(4-(a+b+c))  (I) MR¹ _(d)R² _(e)R³_(3-(d+e))  (II) wherein M is a metal belonging to any of the groups 3to 6 of the Periodic Table or a lanthanum series metal; R¹, R², R³ andR⁴ are each an alkyl group, an alkoxy group, an aryl group, acyclopentadienyl group, an alkylthio group, a substitutedcyclopentadienyl group, an indenyl group, a substituted indenyl group, afluorenyl group, a halogen atom or a chelating agent; a, b and c areeach an integer of from 0 to 4; d and e are each an integer of from 0 to3; and any two of R¹ to R⁴ may form a complex which is crosslinked withCH₂ or Si(CH₃)₂;

wherein R⁹ and R¹⁰ each represent a halogen atom, an alkoxyl grouphaving 1 to 20 carbon atoms or an acyloxyl group; and k is an integer offrom 2 to 20; M¹R¹¹R¹²R¹³R¹⁴  (VII) wherein m¹ is titanium, zirconium orhafnium; R¹¹ and R¹² are each a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group or a fluorenyl group and R¹³and R¹⁴ are each a hydrogen atom, a halogen atom, a hydrocarbon grouphaving 1 to 20 carbon atoms, an alkoxyl group having 1 to 20 carbonatoms, an amino group or thioalkoxyl group having 1 to 20 carbon atoms,but R¹¹ and R¹² may be each crosslinked by a hydrocarbon group having 1to 5 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms and 1to 5 silicon atoms or a germanium-containing hydrocarbon group having 1to 20 carbon atoms and 1 to 5 germanium atoms.
 5. The process accordingto claim 4, wherein M or M¹ is titanium.
 6. The process according toclaim 4, wherein R¹ is a cyclopentadienyl group, a substitutedcyclopentadienyl group, an indenyl group or a substituted indenyl group.7. The process according to claim 5, wherein R¹ is a cyclopentadienylgroup, a substituted cyclopentadienyl group, an indenyl group or asubstituted indenyl group.